Lining drum

ABSTRACT

A lining drum which has a tubular body having open ends, an inlet for compressed air and an outlet for liner is disclosed. The lining drum has end pieces removably attached to the tubular body for closing the open ends of the tubular body, a rotatable shaft inside the tubular body and a crank for rotating the shaft. The end piece has a spring-loaded flange mounting, wherein bias of springs pushes the flange mounting towards the tubular body and a closed position of the flange mounting, and air pressure inside the lining drum pushes the flange mounting away from the tubular body and towards an open position of the flange mounting.

FIELD OF THE INVENTION

The present invention relates to a lining drum for renovating pipelinesand particularly for installing a liner in an existing pipe.

BACKGROUND AND SUMMARY OF THE INVENTION

Installed pipelines in buildings and underground can be rehabilitatedwithout opening structures or digging the ground. The trenchlessrehabilitation enables a quick and durable rehabilitation of pipeswithin buildings and underground pipelines. A resin impregnated liner isinstalled in a pipe with an inversion drum by using air pressure toinvert the liner into the pipe. Typically, a plastic-coated polyesterfelt tube, i.e. the liner, is first impregnated with a synthetic resin.The impregnated liner is closed at one end and wound up inside a liningdrum around a shaft. The open end of the liner is fastened around anoutlet of the lining drum. When pressurized air is supplied to thelining drum, the liner, due to the influence of air pressure, starts toprotrude inside the lining drum, and the protruding liner is directedinto the pipe to be renovated by unwinding the liner from the shaft byrotating the shaft so that the liner starts to extend through the outletof the lining drum.

Once the liner is installed, air pressure is maintained on an elevatedlevel until the resin within the liner settles and the liner forms arigid pipe against the inner surface of the old pipe. The lining drumsof the prior art have been welded together from several metal parts. Theliners can typically withstand pressures from 80 kPa to 200 kPa insidethe liner without rupture when the liner is in an open space. In aconfined space, the liner does not have space to expand or rupture.Therefore, the pressure can rise much higher than the above pressureinterval. For these scenarios, the lining drums have been equipped witha safety valve which opens when the air pressure inside the lining drumreaches 100-300 kPa, depending on the lining drum. Typical output froman air compressor that feeds the lining drum is in a range of 800-1000kPa. Usually a pressure regulator is used between the air compressor andthe lining drum as a third safety feature in addition to the safetyvalve in the liner itself.

One problem associated with the above prior art arrangement is that eventhe three independent safety features do not prevent explosions of thelining drum due to the excessive pressure that builds up inside thelining drum. A liner that is tangled inside the lining drum can blockboth the outlet and the safety valve. An explosion of the lining drum isa potentially a lethal accident and must be avoided at all cost.

One object of the present invention is to provide a low-pressure liningdrum that is safer to use than the lining drums of the prior art becausethe structure of the lining drum does not allow an excessively ordangerously high pressure to build up inside the lining drum.

One advantage of the arrangement of the present invention is that thedevice is safe to use due to the pressure relief arrangement that cannotbe blocked by the liner from the inside of the device.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the present invention is described in greater detailby means of preferred embodiments with reference to the accompanyingdrawings, in which

FIG. 1 is an isometric perspective view of a lining drum according to anembodiment of the present invention;

FIG. 2A is an elevational section view of the lining drum according tothe present invention in a closed position;

FIG. 2B is a detailed view of the section view of FIG. 2A;

FIG. 3A is an elevational section view of the lining drum of the presentinvention shown in FIG. 2A in an open position;

FIG. 3B is a detailed view of the section view of FIG. 3A;

FIG. 4 is an elevational side view of the lining drum according to thepresent invention; and

FIG. 5 is a top view of the lining drum according to the presentinvention;

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1-5 illustrate a lining drum 10 according to an embodiment of thepresent invention. The lining drum of this embodiment, preferably,includes a tubular body 20 that is open at both ends. The tubular bodycould also be closed at one end and have the opposite end being open.The tubular body also includes an inlet 22 on its peripheral surface forreceiving compressed air and an outlet 23 for a liner 60 disposed insidethe tubular body 20 to exit from the lining drum 10. Preferably, thetubular body 20 also includes an inspection window 21 that provides aview inside the lining drum during use of the lining drum so that theviewer can see how the liner rotates inside the tubular body as theliner is extrudes or moves through the outlet 23. Also, a handle 24 forcarrying the lining drum 10 can be attached to the outside of thetubular body 20.

The lining drum 10 has at least one end piece, but in the depictedembodiment there are two end pieces 31, 32. Preferably, the two endpieces 31, 32 are removably attached to the tubular body 20 therebyclosing the open ends of the tubular body. In one embodiment, one endpiece is secured or fixed to the tubular body while the opposite endpiece is removably attached to the tubular body. The tubular body 20 andthe end pieces 31, 32 define a closed container that has the inlet 22that is plugged by an air supply hose (not shown) for receivingcompressed air and the outlet 23 through which the liner extends as theliner is moved into the pipe to be renovated when the lining drum 10 isin use. The air supply hose can thus be used to increase the airpressure inside the lining drum by supplying air into the lining drumvia the inlet 22.

The lining drum 10 also has a rotatable shaft arrangement 51, 52disposed inside the tubular body 20, preferably in the middle of thetubular body extending between centers of the open ends of the tubularbody. The liner 60 is rolled up on the shaft 51 prior to the renovationprocess of the pipe. The shaft arrangement is preferably attached to theend pieces 31, 32 of the lining drum 10 so that the shaft arrangementextends inwardly from the end pieces 31, 32. The shaft arrangement ispreferably rotatably attached to an end piece 31 with a bearing 54 sothat parts of the shaft arrangement can rotate easily in relation to theend piece 31. More particularly, the shaft-arrangement preferablyincludes e.g. a hollow rotatable shaft 51 that extends inwardly from thecenter of the end piece 32 towards center of the opposing end piece 31.The elongated guide 52 is fixedly attached to the center of the opposingend piece 31 at the bearing 54 and extends inwardly towards the centerof the end piece 32 so that the guide 52 is at least partially insertedinside the hollow rotatable shaft 51. However, the rotatable shaft 51does not necessarily have to be hollow and the guide 52 may be attachedto the opposing end piece 31 and has a cavity defined therein forreceiving and accommodating an end of the rotatable shaft 51. The shaftarrangement ensures that the rotatable shaft 51 can be rotated to rollon and off the liner 60 and that the end pieces 31, 32 can be movedfurther apart from each other while maintaining the functionality of theshaft arrangement because the shaft 51 and guide 52 may axially sliderelative to one another, as explained in detail below.

A crank 33 is preferably disposed outside the tubular body 20 and on theoutside of the end piece 32. The crank 33 is fixed or connected to anend 56 of the rotatable shaft 51 of the shaft arrangement for rotatingthe rotatable shaft 51 of the shaft arrangement inside the tubular body20. In other words, by rotating crank 33, the shaft 51 also rotateswithout rotating the end piece 32 or the end piece 31. A remote endportion 58 of the shaft 51 is in rotatable engagement with the bearing54 so that when shaft 51 is rotated the end piece 31 remains stationary.Also, shaft 51 rotates relative to the guide 52 that is inserted intothe remote end portion 58 of the shaft 51 because the guide 52 ispreferably fixedly attached to the inside of the end piece 31 anddimensioned to be inserted into the hollow shaft 51.

The liner 60 to be installed into the pipe to be renovated may first bewound onto the rotatable shaft 51 by rotating the crank 33 and,correspondingly, the liner 60 may be unwound from the rotatable shaft 51by rotating the crank in an opposite direction. As mentioned above, theliner 60 to be installed resides in the lining drum 10 and exits fromthe tubular body 20 through the outlet 23. First, an open end of theliner 60 is pulled inside out, i.e. inverted, over the outer surface ofthe outlet 23 and clamped tight against the outer surface of the outlet23 so that the liner 60 can withstand the pressure increase inside theliner without releasing from the outlet 23.

In order to prevent an excessive or dangerous increase of air pressureinside the lining drum 10 a novel pressure relief system or expansionmechanism for the lining drum has been developed. It was surprisinglyand unexpectedly discovered that at least one of the end piece can beremovably or slidably attached to the lining drum and held tight to thelining drum 10 by a suitable biasing mechanism such as a spring, asdescribed in more detail below. The lining drum 10 of the presentinvention has at least one end piece, such as end piece 32, equippedwith a spring-loaded expansion mechanism that allows the end piece 32 toopen slightly as pressure is building up inside the lining drum 10thereby defining a small gap 62 (best seen in FIGS. 3A-3B) between thetubular body 20 and end piece 32. It is to be understood that theinvention is not limited to having the expansion mechanism only on endpiece 32 and that end piece 31 may also be equipped with the expansionmechanism. When the air pressure inside the lining drum 10 exceeds adefined limit, the force caused by the air pressure exceeds the oppositeforce or bias caused by the biasing device such as spring 41 so that aircan leak out from the lining drum 10 through the gap 62 to reduce theair pressure inside the lining drum 10. The gap 62 is thus created bythe axial movement of the shaft 51 relative to the guide 52 so that theend piece 32 moves away from the lining drum 10 to create the gap 62therebetween. There is also an axial movement occurring inside endprotrusion 35. FIGS. 2A-2B and FIGS. 3A-3B show the details of theprotrusions 25, 35 at the handle 24 but the other protrusions locatedaround the outside periphery of the tubular body 20 (best shown inFIG. 1) are identical. When the air pressure inside the lining drum 10exceeds the limit, there is also and axial movement of the endprotrusion 35 relative to an elongate body such as bolt 40 that isfastened to or screwed into an opening 64 defined in the protrusion 25to hold the end-protrusion 35 (and thus the end piece 32) to the tubularbody 20. An important feature is that the end-protrusion 35 may sliderelative to the bolt 40 against the biasing force of the spring 41, whenthe pressure inside the lining drum 10 exceed the predetermined limit.FIG. 2B shows a contact surface 68 of the end-protrusion 35 sealinglyengaging a sealing surface 66 of protrusion 25 so that an airtight sealis created therebetween. FIG. 3B shows the contact surface 68 beingseparated from sealing surface 66 so that the gap 62 is createdtherebetween and the spring 41 is compressed by the excessiveair-pressure inside the lining drum 10.

When enough air has leaked out from the lining drum 10 and the pressureinside the lining drum 10 has decreased below the limit and so that theair pressure no longer exceeds the biasing force of the spring 41, thespring-loading of the expansion mechanism seals the surfaces 66 againstsurface 68 again and the leaking of air ends. In other words, when theair pressure is too high inside the lining drum 10, it overcomes thebias of the springs and moves the expansion mechanism from a closedposition (FIGS. 2A-2B) to an open position (FIGS. 3A-3B). It isimportant that the biasing force of the spring 41 is strong enough towithstand the air pressure require to install the liner into the pipe tobe renovated. The spring 41 should only give in to pressure that exceedthe predetermined limit to prevent a dangerously high air pressure fromdeveloping inside the lining drum 10. When the air pressure decreasesbelow the predetermine limit inside the lining drum 10, the biasingforce of the spring 41 overcome the air pressure and moves the expansionmechanism from the open position back to the closed position.Preferably, a non-sticky seal 70 is disposed between the tubular body 20and each of the end pieces 31, 32. The seal 70 may, for example, be aring made out of silicone that fits into a groove 72 of the surface 66.

In the preferred embodiment, at least one and more preferably both endpieces 31, 32 are removably attached to the tubular body 20 with thespring-loaded expansion mechanisms, as illustrated in FIGS. 1-5. The endpieces 31, 32 can be e.g. blind flanges that have a convex shape on theoutside and/or a concave shape on the inside of the end pieces andinclude bolt holes close to the periphery of the end pieces. In oneembodiment, the end pieces have protrusions 35 that include holes forreceiving bolts therein. The tubular body 20 also has protrusions 25with threaded cavities so that bolts 40 can be screwed through the boltholes of the end pieces and into the threaded cavities of the tubularbody. The length of the bolts 40 should be long enough so that the boltsdo not tighten the end pieces against the tubular body 20. A gap of 1 to30 mm between the bolt-head and each end piece 31, 32 is preferable. Thegap is preferably surrounded by end protrusion 35 of each end piecethereby defining a cavity 74 for the spring 41 within the end protrusion35. A stem 76 of the bolt 40 goes through the spring 41 and preferably awasher 42 is used between the spring 41 and the bolt-head 78. It shouldbe noted that the bolt-head 78 rests against the washer 42 and cannotslide through the washer 42. However, the end protrusion 35 has anopening 80 defined therein that is dimensioned to snugly but slidablyreceive the bolt head 78 so that the bolt head 78 may slide in theopening 80 as the lining drum 10 moves between the open and closedposition and vice versa. Material, length and other properties of thespring 41 can be adjusted for defining the limit for air pressure whichovercomes the spring bias and opens the expansion mechanism forreleasing air from inside the lining drum. Preferably coil springs areused. When the expansion mechanism opens, air leaks through a large areaand it is virtually impossible that a liner inside the lining drum wouldblock this air leak completely. In an embodiment, a smaller blind flangehaving a spring-loaded expansion mechanism within an end piece can beused similarly but even the smaller expansion mechanism should be to belarger than the outlet 23 to make sure that the liner never blocks theleaking of air in case of excess pressure. In the embodiment shown inFIG. 1, the protrusions 25 and end protrusions 35 are shown as beinglocated on the outside surface of the tubular body 20. It is alsopossible to locate the protrusions 25, 35 on an inside surface of thetubular body 20. It is also possible to locate the protrusions 25, 35 inthe wall of the tubular body 20 so that a portion of the protrusionsextends on radially inwardly on the inside and radially outwardly on theoutside surfaces. The principles described above apply to all of theprotrusions 25, 35 shown in FIGS. 1-5.

The present invention enables the step of predetermining a limit for airpressure inside the lining drum which should never be exceeded to avoiddangerously high pressure from building up inside the lining drum. Thisallows the use of different materials in the tubular body 20 and the endpieces 31, 32. In addition to aluminum, polymers and e.g. rubber canalso be safely used. For example, the tubular body 20 and the end pieces31, 32 can be made of transparent polycarbonate which gives the user anexcellent view inside the lining drum 10. Threads and other criticalparts can be reinforced with metal inserts when using softer materials.

While the present invention has been described in accordance withpreferred compositions and embodiments, it is to be understood thatcertain substitutions and alterations may be made thereto withoutdeparting from the spirit and scope of the following claims.

I claim:
 1. A lining drum, comprising: a tubular body having at leastone open end, the tubular body having an inlet and an outlet definedtherein; an end piece removably attached to the open end of the tubularbody, the end piece being movable between a closed position to close theopen end of the tubular body and an open position to open the open endof the tubular body; a rotatable shaft arrangement disposed inside thetubular body and extending from said end piece, the shaft arrangementhaving a shaft and a guide; a crank disposed outside the tubular bodyand fixed to the shaft arrangement for rotating the shaft of the shaftarrangement, and the end piece having a spring-loaded end-protrusion inoperative engagement with a protrusion of the tubular body, the endpiece being movable between a closed position and an open position byaxially sliding the shaft relative to the guide against a biasing forceof the spring-loaded end-protrusion, the end piece and the tubular bodyhaving a gap defined therein when the end piece is in the open position.2. The lining drum of claim 1, wherein the tubular body has two openends defined therein and the lining drum has a second end pieceremovably attached to the tubular body.
 3. The lining drum of claim 2,wherein the second end piece is removably attached to the tubular bodywith a second spring-loaded end-protrusion.
 4. The lining drum of claim2, wherein the shaft is a hollow rotatable shaft extending from a centerof the end piece towards a center of the second end piece, and the guideis fixedly secured to a center of the second end piece and extendstowards the center of the end piece and the guide is at least partiallyinserted inside the hollow rotatable shaft.
 5. The lining drum of claim1, wherein the end piece is removably attached to the tubular body withthe spring-loaded end-protrusion.
 6. The lining drum of claim 1, whereinthe spring-loaded end-protrusion is movably attached to the protrusionof the tubular body with a bolt, the bolt being axially movable relativeto the spring-loaded end-protrusion, the bolt having a spring urging theend piece towards the tubular body.
 7. The lining drum of claim 1,wherein a non-sticky seal is disposed between the tubular body and theend piece.